Method and device for reducing noise coefficient of analog optical fiber link

A noise figure and analog optical fiber technology, applied in the field of optoelectronics, can solve problems such as increased insertion loss, achieve the effect of reducing link noise figure and breaking through technical bottlenecks

Active Publication Date: 2016-12-07
HUNAN INST OF TECH
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Problems solved by technology

However, as the transmission distance increases, the insertion loss of traditional transmission media such as cables and waveguides increases rapidly, especially in the microwave and millimeter wave frequency bands. The bottleneck of large insertion loss limits the microwave link more and more obviously. Typical coaxial cables The loss in the X-band is higher than 1.8dB / m (1.8×10 3 dB / Km), while the loss of commercial SMF-28 communication fiber at 1.5um wavelength is only close to 0.2dB / Km

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  • Method and device for reducing noise coefficient of analog optical fiber link
  • Method and device for reducing noise coefficient of analog optical fiber link
  • Method and device for reducing noise coefficient of analog optical fiber link

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Embodiment 1

[0033] refer to figure 1 , showing the basic structure of a commercial analog fiber optic link. The link mainly includes a laser 1, which provides a modulated light source; a polarization controller 2, which is used to control the polarization direction of the laser; an electro-optic modulator 3, which realizes microwave-to-optical conversion; an amplifier 4 (preferably a low-noise amplifier), which uses It is used to amplify the input signal and cascade the optical fiber link (namely the optical fiber 5) to reduce the noise figure of the entire link; a photodetector 6 realizes light-to-microwave conversion. The electrical signal is modulated to the amplitude of the optical carrier by the electro-optic modulator, and then restored to an electrical signal at the output of the photodetector after being transmitted in the optical fiber. For a typical intensity modulation-direct demodulation microwave optical link, its noise figure can be expressed as

[0034] F ...

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Abstract

The invention discloses a method and device for reducing a noise coefficient of an analog optical fiber link. The method comprises the steps that after same modulation is carried out on at least two lasers of different wavelengths, the lasers are received and demodulated into electric signals by corresponding optical detectors; analog signals are converted into digital signals, and the digital signals enter a cross-correlation processing system for cross-correlation processing; correlated parts in the electric signals are reinforced, uncorrelated parts in the electric signals are weakened, and the noise coefficient of the analog optical fiber link is reduced; and the electric signals are converted into the analog signals and then are output. According to the method and the device, through introduction of a double-laser-double-optical detector structure, the cross-correlation processing is carried out on the received signals by employing a cross-correlation technology; the correlated useful signals are reinforced; the uncorrelated parasitic noise is weakened; and finally the noise coefficient of the analog optical fiber link is reduced. The method and the device also can be applied to the input digital signals, and the cross-correlation processing can be directly carried out without carrying out analog to digital and digital to analog conversion.

Description

technical field [0001] The invention belongs to the technical field of optoelectronics, and in particular relates to a method and a device for reducing the noise factor of an analog optical fiber link. Background technique [0002] Glossary: [0003] In the field of signal processing, cross-correlation (sometimes also called "cross-covariance") is a measure used to express the similarity between two signals, and is usually used to find properties in unknown signals by comparing them with known signals. It is a function of time between two signals, sometimes called a sliding dot product, and is a commonly used digital signal processing method in the fields of communication, pattern recognition, and cryptanalysis. [0004] Traditional microwave links are an important part of many commercial and military communication systems, and can be widely used in aerospace, radar, electronic warfare, high-frequency communication, remote sensing and telemetry, and precision measurement. ...

Claims

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Application Information

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IPC IPC(8): H04B10/25H04B10/61
CPCH04B10/25H04B10/61
Inventor 洪俊李祖林姚胜兴王小虎刘海波张啸宇胡昭
Owner HUNAN INST OF TECH
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